Regenerative coke oven



June 1, 1937. c T

REGENERATIVE COKE OVEN Filed Jan. 20, 1934 2 Sheets-Sheet ATTOR N EYJune 1, 1937. c. OTTO REGENERATIVE COKE OVEN Filed Jan. 20, 1934 2Sheets-Sheet 2 Uh MQ Patented June 1, 1937 UNITED STATES REGENERATIVECOKE OVEN Carl Otto, Essen, Germany Application January 20, 1934, SerialNo. 707,485 In Germany October 6, 1933- 10 Claims.

This invention relates to regenerative ovens intended for the productionof gas and coke of that class of oven comprising coking chambersalternating with heating walls each containing a great number of heatingfiues, in which each two rows of heating flues cooperating according tothe reversal of flow are in communication by channels which run over thecoking chambers situated between therespective heating walls. In a knownconstruction of such oven the heating flues are united in groups ofabout five fiues. The heating flues of such a group open into an upperhorizontal channel and the horizontal channels of neighboring heatingwalls are interconnected by ducts extending over the intermediate cokingchamber. This construction suffers from the drawback of considerabledifferences of pressure arising due to the sudden changes of directionand speed the gas undergoes in the passage from one heating wall to theother. In addition, the resistances of the gas are not uniform in allthe heating fiues, so that special regulating means must be provided, inorder to obtain an absolutely uniform heating effect.

The present invention has for its object to overcome this drawback whichobject is achieved by the fact that only two heating fines of differentrows of heating fiues are interconnected by a special connecting channelwhich extends over the intermediate coking chambers. This connectingchannel is U-shaped and its upper horizontal portion has a much smallercross sectional area than the heating flues interconnected by it. Thiscross sectional area, however, is determined so as not to be smallerthan required for the maintenance ofa laminary flow. The constriction ofthe channel from the cross section of the heating flue to its smallestcross section takes place gradually in the vertical portion of thechannel which portion is the direct. pro longation of the respectiveheating flue. The connecting channel thus acts like a Venturi pipe anddoes not cause any additional resistances worth mentioning in the pathof the gas. Furthermore, a gradual transformation .from the rectangularcross section of the heating fiues to the preferably circular crosssection of the connecting channel may be provided in the constrictedportions.

Furthermore, instead of each one heating flue of two heating walls, twoneighboring heating fiues of two heating walls may be interconnected byone sole such connecting channel which leads over the intermediatecoking chambers. The upper ends of the heating lines in this case arethermal decomposition.

united with slight inclination and open in common into the verticalportions of the U-shaped connecting channel. Preferably also theconstriction is provided in the inclined portion as well as a gradualtransformation of the rectangular cross sections of the heating flue tosemicircular ones which unite to a circular cross section on the placewhere the heating fiues open into the vertical portion of the connectingchannel.

The refractory brickwork above the coking chambers of course is morehighly heated by the connecting channels, even if a great speed of thegas prevails in the latter and the heat radiation is kept low by theapplication of laminary flow. The increase in temperature of thebrickwork above the coking chambers tends to the heating of the gases ofdistillation produced in the respective coking chambers and suckedthrough the upper gas collecting spaces thereof into the hydraulic mainsto a temperature high enough to produce decomposition of those gases. Itis, therefore, a further object of the invention to avoid suchdecomposition. This object'is attained by the provisions made forpassing the gases of distillation from the oven chambers to thehydraulic main. These provisions include a number of openingsdistributed along the entire length of the top of each coking chamberand connecting the latter to ahorizontal gas dis charge duct provided inthe oven cover and extending parallel to the length of the oven chamberand connecting the latter to the hydraulic main. Such gas dischargeducts in the oven cover are well-known per se. The arrangement accordingto the invention, however, is peculiar in so far as the U-shapedchannels connecting the heating fiues of different heating walls extendabove the coking chamber at a sufiicient distance below the gasdischarge ducts in the oven cover, so that the latter are not heated toan extent worth noting from the connecting channels and thus remain coolenough to secure a discharge of the gases of distillation without Incoking chambers which possess only one central filling hole the gasdischarge ducts begin in the vicinity of the latter and lead on bothsides to the two hydraulic mains situated on theends of the cokingchamber.

Advantageously regulating means are provided on the places of connectionbetween the top gas collecting space and the gas discharge ducts in theoven cover, so that a more or less great cross sectional area can beestablished here. In this manner the gas of distillation can-be causedto flow in a determined ratio immediately through the top gas collectingchamber and through the gas discharge duct.

For, tests have shown that the gas of distillation escaping from a coalcoked at a determined temperature has different composition if after itsproduction it is led through spaces of different temperature. Inparticular, it has been found that the yield of benzole and ofhydrocarbons of similar properties, at a medium temperature of the spacethe gases must traverse after their production first is lower than atsomewhat higher temperatures, tor example 800 C. for a certain sort ofcoal, and that with further increase of the temperatures of said spacethe yield of benzole etc. sinks again. Thus there is a maximum yield ata determined temperature of the space.

According to the coking times or to the final 0 temperatures employed inthe coking operation, therefore, in order to obtain a maximum yield ofbenzole etc., the gases must traverse spaces the temperature of whichmust be not too high and not too low. By adjusting the cross sectionalarea of the openings of the top gas collecting space into the gasdischarge duct and by suitably regulating the suction it is thuspossible to cause the gases of distillation to remain a longer orshorter period of time in the gas collecting space and in the saidopenings and to obtain in this manner a maximum yield of benzole andbenzolelike hydrocarbons under the varying conditions of operation ofthe coking plant.

In order that the invention may be clearly understood and readilycarried into effect, two embodiments of chamber ovens, according to theinvention, are illustrated by way of example in the accompanyingdrawings in which the Figures 1a to 4a show an embodiment in which eachone heating flue of a heating wall may cooperate with a heating flue ofanother heating wall for series flow through the two flues in eitherdirection, while in the embodiment shown in Figures 112 to 4b twoneighboring heating flues of every heating wall are united and connectedwith two corresponding heating flues of a neighboring heating wall byone sole channel leading over the coking chambers. In particular Figures1a and lb are vertical sections of the top portion or a chamber ovenbattery, seen in the longitudinal direction of the latter and, re-

spectively, on lines IaIa of Figure 3a and Ib-Ib of Figure 31),

Figures 2a and 2b are sections parallel to the first-named ones, on line11-11 of Figures 4a and Figures 3a. and 3b are vertical sections seen inthe longitudinal direction of a heating wall through the top ends of theheating flues, on the 0 lines IIIa-IIIa and IIIb-IIIb of Figures 1a and112, respectively,

Figures 4a and 4b are vertical sections of the top portion of a cokingchamber in the longitudinal direction thereof, on the lines IVaIV and 5IVb-IVb of Figures 1a and lb, respectively, and.

Figure 5 shows four horizontal sections of the upper constriction of theheating flues, on the lines A, B, C, D of Figure 3b.

In the arrangement of Figures la to 4a rows of vertical heating flues 2are provided between the horizontal coking chambers I. The heating flues2 attop open into constrictions 3 interconnected by a connecting channel4 which extends above the intermediate coking chamber. Two 7 neighboringheating walls need 991 P9 y be interconnected by such connectingchannels 4, but also more distant heating walls may cooperate in thereversal of the flow. Thus, it is pos sible for instance to connectwithin a group of four adjacent heating walls. the heating flues of thefirst wall with those of the third and the flues of the second wall withthose 01' the fourth. Also the heating flues of the first and fourth andthose of the second and third wall may be interconnected and cooperatein the reversal of the flow.

The gases oi. distillation are sucked from the coking chambers notdirectly from the gas collecting space situated above the charge, butthrough special gas discharge passages 5 provided in the oven cover andcommunicating with the collecting spaces by a number of vertical ducts 8distributed on the entire length of the chamber. By means of damperbricks I the size of the openings 6 can be regulated as desired. Fromthe ducts 5 the gases are sucked through ascension pipes 8, situated atthe ends of the chambers, into the hydraulic main (not shown). Thechambers are charged each through one sole central filling hole 9.

The embodiment illustrated in Figures 1b to 4b differs from thatdescribed by each two neighboring heating flues being united upwardlyand connected by a common connecting channel with two heating flues of aneighboring wall, with which they cooperate in the reversal of the flow.The constrictions I0 01' the heating flues are somewhat inclined to oneanother so as to unite at their narrowest portion, where they form theconnect ing channel H proper. The advantage of this arrangement residesin the feature that the number of the connecting channels is reduced onehalf whereby the construction of the oven cover is simplified.

It will be seen by the section of Figure 5, how the rectangular crosssection of the heating flues within the constriction goes over into asemicircular one from which then results the circular cross section ofthe connecting channel I l proper.

Such variation inthe cross sectional shape of the 'cross over connectionis especially advantageous for the purposes of applicant's invention,since it contributes to a desirably small pressure drop in the crossover connection, and to the maintenance of laminar flow in the circular,most restricted portion of the connection. As is well known, thetendency of the flow to pass from the laminar into the turbulentcondition increases with an increase in the velocity of the flow whichresults from a restriction in the cross section of the flow passage. Thelaminar flow can be maintained with a higher flow velocity in a flowpassage of circular cross section than in a flow passage of any othercross section. Since the vertical heating flues are necessarilyrectangular, or approximately rectangular in cross-section, theformation of the tapering lower portions of the cross over connectionwith rectangular cross sections, permit those tapering lower portions tomerge smoothly into the vertical heating flues, thereby avoiding flowdisturbing eddies which interfere with the maintenance of laminary flowand increase the pressure drop through the cross over connection. As hasbeen pointed out, applicant's cross over connection is in eflect aVeraturi flow passage, and this, of itself, contributes to a lowpressure drop in the connection. The full advantage of a Venturi flowpassage in minimizing pressure drop requires a suitably smooth mergingof the ends of the Venturi passage proper -make the diameter and crosssection of the throat portion of the channel as small as is practicallypossible. To minimize the gas pressure reduction,-or loss of pressurehead, in the channel, and to minimize the heat transfer through thechannel wall, it is practically desirable, however, that the throatportion of the cross-over channel should have a cross section largeenough to insure a laminary fiow through the channel, with the maximumvolume of gas flow through the channel under normal operatingconditions. With the proportions shown in Fig. 5, the cross section ofthe throat is approximately one tenth of the cross section of the twoflues 2 to which the cross-over channel is connected at either end, sothat the velocity of flow through the throat portion of the cross-overchannel is about ten times the velocity of flow in the upper portion ofeach flue 2 delivering heating gases to, or receiving such gases fromthe channel. This ten to one ratio of cross sections and flow velocitiesrepresents a safe practical compromise, in the oven arrangement shown inFigs. 30-5, between the desire on the one hand to make the cross sectionof the throat portion of the channel as small as is practicallypossible, and the desire on the other hand to maintain a laminary flowthrough the cross-over cha nnel with the maximum normal velocity of flowtherethrough.

What I claim is:

1. An oven for producing gas and coke comprising alternate cokingchambers and heating walls arranged side by side, vertical heating fluesin each heating wall arranged side by side in a row extendinglongitudinally of said wall, and channels communicably connecting theupper ends of flues in each heating wall to the upper ends of flues inanother heating wall, each of said channels being of inverted U-shapeand comprising one leg portion extending upward from and communicatingat its lower end with a flue or flues in one heating wall, a second legportion extending upward from and communicating at its lower end withaflue or flues in another heating wall, and a portion intermediate theupper ends of said leg portions, and each of said channels forming asingle Venturi tube form flow path having end portions tapering in crosssection along their lengths and formed by the corresponding legportions, each of the latter diminishing in cross section from its lowerend to its connection withsaid intermediate portion, and having a throatportion formed by the said intermediate portion of the channel and of across section not greater than the minimum cross section of eachcorresponding leg portion. 7

2. A regenerative oven for producing gas and coke comprising alternatecoking chambers and heating walls arranged side by side, verticalheating flues in each heating wall arranged side by side in a rowextending longitudinally of said wall, and channels communicablyconnecting the upper ends of flues in each heating wall to the upperends of flues in another heating wall, each of said channels being ofinverted U-shape and comprising one leg portion extending upward fromand communicating at its lower end with .aflue or flues in one heatingwall, a second leg portion extending upward from and communicating atits lower end with a flue or flues in another heating wall, and aportion intermediate said leg portions, and each of said channelsforming a single Venturi tube form flow path having end portionstapering in cross section along their lengths and formed by thecorresponding leg portions, each of the latter diminishing in crosssecticn'from its lower end to its connection with said intermediateportion, and having a throat portion formed by the said intermediateportion of the channel and of a cross section not greater than theminimum cross section of each corresponding leg portion, the said legportions of each channel-being similar in form, sothat its Venturi tubeflow action is; the same for flow through the channel in eitherdirection.

3. An oven for producing gas and coke comprising alternate cokingchambers and heating walls arranged side by side, vertical heating fluesin each'heating wall arranged side by side in a row extendinglongitudinally of said wall, and channels communicably connecting theupper ends of flues in each heating wall to the upper ends of flues inanother heating wall, each of said channels being of inverted U-shapeand comprising one leg portion extending upward from and communicatingat its lower end with a flue or flues in one heating wall, a second legportion extending upward from and communicating at its lower end with aflue or flues in another heating'wall, and a portion intermediate saidleg portions, each of said channels forming a single Venturi tube formflow path having end portions tapering in cross section along theirlengths and formed by the corresponding leg portions, each of the latterdiminishing in cross section from its lower end to its connectionwithsaid intermediate portion, and having an elongated throat por-- tionformed by the said intermediate portion of the channeL'and of a crosssection approximately constant along its length and not greater than theminimum cross section of each corresponding leg portion.

4. An oven as specified in claim 10in which each Venturi tube flow pathforming channel is proportioned relative-to the volume of heating gasflow there-through to insure a laminary flow through the throat portionof the path with the maximum normal volume of heating gas flow throughthe channel.

5. An oven as specified in claim 1 in which each leg portion of eachVenturi tube flow forming channel is bifurcated at its lower end withone bifurcation communicating with one and the other bifurcationcommunicating with another vertical heating flue.

6. An oven as specified in claim 1 in which each of said channels variesgradually in cross sectional contour from a circular form in the portionintermediate its ends, into a rectangular form adjacent each heatingflue with which it communicates.

'7. An oven for producing gas and coke comprising alternate cokingchambers and heating walls arranged side by side, vertical heating fluesin each heating wall arranged side by side in a row extendinglongitudinally of said wall, channels communicably connecting the upperends of flues in each heating wall to the upper ends of flues in anotherheating wall, each of said channels being of inverted U-shape andcomprising one leg portion extending upward from and communicating atits lower end with a flue or flues in one heating wall, a second legportion extending upward from and communicating at its lower end with aflue or flues in another heating wall, and a portion intermediate saidleg portions and extending over the top of each coking chamber betweenthe flues with which the said leg portions respectively communicate. andeach of said channels forming a single Venturi tube form flow pathhaving end portions tapering in cross section along their lengths andformed by the corresponding leg portions, each of the latter diminishingin cross section from its lower end to its connection with saidintermediate portion, and having a throat portion formed by the saidintermediate portion of the channel and of a cross section not greaterthan the minimum cross section of each corresponding leg portion, and ahorizontal distillation gas discharge duct above and parallel to eachcoking chamber and vertically displaced from said channels, and passageshorizontally displaced from said channels and connecting said duct tothe top of the chamber at points distributed along the length of thelatter.

8. An oven for producing gas and coke comprising alternate cokingchambers and heating walls arranged side by side, vertical heating fluesin each heating wall arranged side by side in a row extendinglongitudinally of said wall, channels communicably connecting the upperends of flues in each heating wall to the upper ends of flues in anotherheating wall, each of said channels being of inverted U-shape andcomprising one leg portion extending upward from and communicating atits lower end with a flue or flues in one heating wall, a second legportion extending upward from and communicating at its lower end with a.flue or flues in another heating wall, and a portion intermediate saidleg portions and extending over the top of eachcoking chamber betweenthe flues with which the said leg portions respectively communicate, andeach of said channels forming a single Venturi tube form flow pathhaving end portions tapering in cross section along their lengths andformed by the corresponding leg portions, each oi'the latter diminishingin cross section from its lower end to its connection with saidintermediate portion, and having a throat portion formed by the saidintermediate portion of the channel and of a cross section not greaterthan the minimum cross section of each corresponding leg portion, and ahorizontal distillation gas discharge duct above and parallel to eachcoking chamber and above the level of the tops of'said channels, andpassages horizontally displaced from said channels and connecting saidduct to the top of the chamber at points distributed along the length ofthe latter.

9. An oven as specified in claim 1, in which the cross section of thethroat portion of the said Venturi tube form flow path is not greaterthan approximately one tenth of the cross section of the flue or fluesto which said path is connected at either end.

10. An oven as specified in claim 1, in which the cross section of thethroat portion of the Venturi tube form flow path is a relatively smallfraction only of the cross section of the flue or flues to which saidpath is connected at either end, but is large enough for the maintenanceof laminary flow through said path with the maximum normal volume ofheating gas flow therethrough.

CARL OTTO.

